DIASTROPHISM AND THE FORMATIVE PROCESSES 3 



all constituent elements and for such chemical combinations as are 

 possible, except in so far as the heat itself stands in the way. With 

 such extraordinary facihties for selective adaptation as were 

 hypothetically offered by the passage of the earth substance from 

 the assigned gaseous to the Hquid state and thence at length on 

 to the solidifying state, a large part of all possible adaptation to 

 the demands of pressure — save those restrained by heat — should 

 have taken place before the record of diastrophism began. About 

 all shrinkage left to be registered would be the meager amount that 

 might spring from cooling. 



Thus in several vital ways the inherited theory of a molten 

 earth came to be a source of embarrassment to investigators who 

 were struggling with the specific demands made by the field evi- 

 dences of actual diastrophism. 



THE WORKING FITNESS OF THE ALTERNATIVE VIEW 



However, the case was desperate only from the traditional 

 point of view. These embarrassments may be avoided if the 

 gaseo-molten, hypothesis is replaced by some form of the view 

 that the earth was built up by the accession of solid particles 

 brought to the earth in succession at intervals. In an earth so 

 built the aggregate should have retained very nearly its maximum 

 resources of combination, adjustment, and compression, while at 

 the same time it was contributing only a small measure of heat to 

 embarrass the threatened oversupply from radioactivity. 



Furthermore, this view affords an easy and natural explanation 

 of the concentration of radioactive substances at the surface. 

 Under this view the radioactive particles came to the earth at 

 random with the rest of its material. Their spontaneous heat was 

 readily radiated away until they became buried to depths that 

 prevented its ready escape. They then tended to become centers 

 of local liquefaction. In so far as this was reaHzed they became 

 enveloped in their own mobile products and were thus carried by 

 the extrusive agencies up to the cold zone or the surface. The 

 liquid blebs thus generated, carrying their self-heaters with them, 

 were well equipped for making exchanges with the eutectic sub- 

 stances encountered on their way out and for concentrating these 



